FIG. 8 shows a schematic perspective view of such a magnetic field sensor 3. From a plastic housing side 10, four flat conductors 6 to 9 protrude from a plastic housing 11. Arranged in the plastic housing 11 is a semiconductor chip 4, the position of which in the housing 11 is shown by dashed lines in FIG. 8. Four contact pads 32 to 35 are arranged on the top side of the semiconductor chip 4, said contact pads being electrically connected to the flat-conductor electrodes 6 to 9 by means of corresponding connecting elements 36 to 39 within the plastic housing 11. If a current is impressed between the flat-conductor electrodes 6 and 9 and the plastic housing 11 is positioned with the semiconductor chip 4 in a magnetic field gap, then a measurement voltage dependent on the magnetic field strength in the magnetic field gap and on the impressed current occurs at the flat-conductor electrodes 7 and 8 as measuring electrodes. In order, from a circuit board, to introduce such a magnetic field sensor 3 into a magnetic field gap, through-contact openings are to be provided in the circuit board in order to electrically connect the printed circuit of the circuit board to the four flat-conductor electrodes. This is illustrated in FIG. 9, which shows a schematic cross section through a magnetic field measuring device 40 in accordance with the prior art. In order to measure for example the current through a lead, the latter is surrounded by a soft-magnetic ring 41 having a magnetic field gap 12, into which is inserted the magnetic field sensor 3 in accordance with FIG. 9 with its semiconductor chip 4 and the flat-conductor substrate 5, on which the semiconductor chip 4 is fixed. The circuit board 24 with its populated top side 23 and its underside 26 has a contact hole 42, into which one end 43 of the flat-conductor electrode 6 is soldered. Soldering-in and fixing four flat-conductor electrodes 6 to 9 of this type necessitates manual handling. The latter requires personnel costs and is not accessible to automatic production.
The document DE 10 2006 057 970 A1 discloses a semiconductor device comprising a magnetic field sensor, which is surface-mountable on a circuit board. A corresponding magnetic field measuring device which is possible with a surface-mountable magnetic field sensor of this type is shown in FIG. 10. In order in this case to measure the magnetic field strength in a magnetic field gap 12, it is necessary for the surface-mountable magnetic field sensor 45 to be positioned with the circuit board 24 in the gap 12, with the disadvantage that this requires a significantly wider measurement gap in the soft-magnetic ring 41. In addition, the alignment of the circuit board 24 is then predefined with the magnetic field gap 12, which is unfavorable in many applications, for which reason the embodiment in accordance with FIGS. 8 and 9 may be preferred for magnetic field sensors, which embodiment, however, precludes cost-effective surface mounting by means of, for example, an automatically operating automatic placement machine.